The iSBX bus is a unique interface facilitating onboard expansion with iSBX Multimodule boards. The iSBX bus is derived directly from the on-board CPU bus and, as such, an iSBX Multimodule board plugged into the iSBX bus becomes an integral element of the single board computer. The physical interface between the single board computer and the iSBX Multimodule board is a unique connector designed specifically for the iSBX bus. The iSBX bus is brought out to a female iSBX bus connector on the single board computer and mates with its male equivalent resident on the iSBX Multimodule board.
The iSBX Multimodule board concept offers a unique design approach to board level users. To date, the designer has had a broad range of single board computers and expansion boards joined together on the Multibus interface. The iSBX Multimodule boards bring a new concept to expansion, providing a product family of smaller modules that can be plugged directly onto the single board computer. These boards come in two sizes. The single wide board is 3.70 inches long and the double wide board is 7.50 inches long. In short, the user may now tailor his application directly onboard the single board computer at a minimal cost. In addition, the iSBX Multimodule boards offer maximum 8-bit performance because it is tightly coupled to the microprocessor through the iSBX bus.
The iSBX bus concept can be expanded to 8/16-bit I/O operations by simply adding 8 data lines and redefining the chip select lines. Both the 8- and 16-bit iSBX Multimodule boards will operate on a 16-bit base board. Physically, the mounting holes on both the 8- and 16-bit iSBX Multimodule boards are identical. The 8-bit iSBX Multimodule connector is a subset of the 16-bit iSBX Multimodule connector. An 8-bit iSBX Multimodule board operating on a 16-bit base board will do all I/O operations with the lower data byte (DATO-DAT’7).
The iSBX Multimodule board specifications are defined in a similar way an I/O component would be.